Firms’ international scope of activities and growing workforce mobility foster the development of teams which are composed of members with different cultural backgrounds. Research on cultural diversity has found large inconsistencies concerning the effects of multicultural team compositions. This led to seeing cultural diversity as a double-edged sword with a potential to yield positive and negative effects in organizations. In contrast to much previous cultural diversity research, this work has conceptualized and measured cultural diversity as deep-level diversity across multiple cultural value dimensions. With a sample of 97 international and multicultural entrepreneurship teams, this research empirically tested effects of two forms of cultural diversity (separation and variety) on team processes and effectiveness. Findings show that cultural diversity in the form of variety has the positive effect of higher creativity in teams, while cultural diversity as separation has negative effects of lower communication quality and lower creativity. The effects of diversity on creativity, however, do not further influence team innovativeness. In addition to the main effects, the results include mediating effects with team processes of communication, task conflict, and task reflexivity. The thesis discusses theoretical implications for diversity research and provides suggestions for practitioners in global team management.